Stacked stencil assembly package



Dec. 10, 1963 L. R. MOONEY 3,113,671

STACKED STENCIL ASSEMBLY PACKAGE Filed July 11, 1960 INVENTOR. IA wzzwc'z P. Moons? ATTORNEY United States Patent M 3,113,671 STACKED STENCIL ASSEMBLY PACKAGE Laurence R. Mooney, St. Paul, Minn, assignor, by mesne assignments, to Sten-C-Labl, Inc., St. Paul, Minn, a corporation of Minnesota Filed July 11, 1960, Ser. No. 41,867 3 Claims. (Cl. 206-60) This invention relates generally to a stacked stencil assembly package and particularly to such a package wherein each stencil assembly includes an exposed pressure sensitive adhesive surface portion for attachment thereof to a larger sheet when used.

Reference is made to my prior US. Pat. No. 2,771,026 in which stencil assemblies are disclosed and claimed each of which includes a stencil sheet, an underlying carbon sheet adhesively connected to the stencil sheet and a non-drying pressure sensitive adhesive for attaching the stencil and carbon sheets to a larger sheet. In the past, the adhesive and carbon surfaces have been protected by adhering a hacker sheet to the adhesive surface which backer sheet also underlies the carbon sheet and is held in place by being adhered to the adhesive. This backer sheet must then be removed from the assembly before the stencil can be applied to the larger sheet for use. This is time consuming and has therefore been somewhat objectionable.

I have also discovered that whenever these stencil assemblies with the backer sheets attached are stacked one on top of the other the adhesive normally used will under extreme temperature and humidity conditions an d over extended storage periods, become plastic and bleed out around the edges of the web of the tape to which said adhesive is applied and this, of course, will expose areas of adhesive which has flowed out beyond the tape web, to the overlying backer sheet of the stencil assemgly disposed immediately thereabove, this will cause each upper stencil to adhere to the next lower one and make it diificult to separate each individual stencil from the others.

It is an object of the present invention to provide a package including a container in which stencils are stacked and confined and wherein an adhesive repellent separator sheet is interposed between adjacent stencils to maintain the stencils entirely separate from each other and permit the same to be easily removed individually from the container.

More specifically it is an object to provide a package including stencil assemblies having an adhesive attachment portion and disposed in stacked relation one on top of the other with separator sheets having adhesive repellent surfaces on both sides thereof interposed between adjacent stencils to positively prevent the same from adhering together and having slightly greater width and length dimensions than the stencil sheets, said package also including a container having slightly greater length and width dimensions than the separator sheets in order to facilitate easy one at a time removal of the stencils from the container and eliminating the preparatory step of initially removing a hacker sheet from the stencil before applying the same to a larger sheet.

These and other objects and advantages of this invention will more fully appear from the following description made in connection with the accompanying drawing, wherein like reference characters refer to the same or similar parts throughout the views and in which the FIGURE is a perspective view of my new package with portions of the container broken away and with the upper stencils and separator sheets turned back for purposes of illustration.

In the drawing, a plurality of stencil assemblies designated as an entirety by the numeral A are shown stacked 3,113,671 Patented Dec. 10, 1963 one upon the other and are confined within a suitable container B within which the same are shipped and stored. This provides a convenient package from which the stencils can be easily removed one at a time for use.

Each stencil assembly A has a carbon sheet 10, a stencil sheet 11 and an overlying strip of tape 12 having a pressure sensitive non-drying adhesive surface.

The carbon sheet and stencil sheet are staggered along the upper edges thereof in order to permit the tape 12 to be adhered to the upper marginal portions of both of said sheets and securely hold the same together in the desired registered relation as described in my previously identified US. Pat. No. 2,771,026. The portion of the tape left exposed is used to secure the carbon and stencil assembly to an invoice or other business form.

In my present invention, I interpose between the adjacent stacked stencils a separating sheet 13 which has a suitable adhesive repellent surface on both sides thereof which will positively prevent the exposed adhesive on the tape 12 from adhering thereto. Previously where a hacker sheet was adhered to the overlying stencil excessive temperature and humidity conditions and/or excessive aging, caused bleeding of the adhesive around the edges of the hacker tape so that the backer sheet of the overlying stencil assembly would stick to the underlying stencil assembly and all of the stacked stencils would thus become adhered together into a single mass. While this degree of adhesion was often not great it was suflicient to make it difficult to remove the individual stencils from the others under such conditions.

In the present invention, however, I incorporate a separating sheet with a repellent surface on both sides which is interposed between adjacent stencils. This provides a repellent surface on both sides of each stencil assembly and even though the adhesive might bleed out around the edges of the tape, the same Will not stick to the repellent surface of the separating sheet 13 and thus the stencil assemblies will remain loose and individually removable from the container or box B. When removed from the box, the stencils are immediately ready for use without requiring the removal of a backer sheet which was previously necessary and the shelf life of the stencils will be materially increased since the individual assemblies will be constantly separated from one another and will always be loose within the container.

Pressure sensitive adhesives of the type generally used in this construction are comprised of highly cured synthetic rubbers which have incorporated with them various anti-oxidants, tackifiers, and other control reagents. Similar adhesives may also be constructed from low molecular weight acrylics, from acrylonitrile synthetic rubber types, or from polyisobutylene derivatives. In all cases except the straight acrylics the synthetic rubbery material is highly cured, that is, the rubber is oxidized or otherwise chemically affected so as to reduce the wet grab of the adhesive.

It is necessary for such a repellent sheet to be free from migration and to remain active as a repellent to the adhesive used for extended periods of time and it is also important that the same does not attack the adhesive used in my stencil assemblies. After considerable experimentation, I have found that polysilicone resin coatings on a paper or other backer sheet performs satisfactorily to repel adhesives presently used for my stencil assemblies. The Dow-Corning Company of Midland, Michigan, manufactures and sells such repellent silicones and identifies these as DC 22 and DC 23. While the exact chemical nature of the polysilicone resin used for this repellent coating is not specifically known, it is believed that the same is basically a dimethyl polysiloxane. These silicones are supplied as emulsions which are coated onto the paper, dried, and then placed in jumbo roll form in a curing room Where elevated temperatures drive out any low molecular Weight silicon chains. These low molecular Weight chains are primarily responsible for the silicone poisoning of adhesives in previously used siliconcs.

As illustrated in the drawing the container B consists in a cardboard box having closure flaps in the ends thereof with the flap at one end being removable along an arcuately perforated line 14 which will provide an access opening in the top panel of the box and produce a dispensing container from which the individual and separated stencil assemblies may be easily and readily removed. It is to be noted that the dimensions of the container are slightly greater than the separator sheets and at least the width dimension of the separator sheets is slightly greater than the Width dimension of the stencil assemblies thus further facilitating removal of the stencil assemblies from the container.

It will be seen that I have provided a new and highly efficient package wherein such stacked stencils will remain entirely separate from each other and can be individually removed from the packaging box or container in a readyto-use form without performing any preparatory operation thereon. This package not only produces a package which materially increases the shelf life of the stencils, as has been described, but also one which is capable of materially increasing the efficiency of the use thereof.

It will, of course, be understood that various changes may be made in the form, details, arrangements and proportion of parts without departing from the scope of my invention, which generally stated consists in the matter set forth in the appended claims.

What is claimed is:

1. A package comprising a plurality of stacked stencil sheets of the type having a normally tacky non-drying adhesive portion, a separator sheet having adhesive repellent surfaces on both sides thereof and interposed between adjacent stencils to positively separate the same from each other and a container for confining said stacked stencils and separator sheets for shipment and storage and including means for opening the container to provide ac cess to the stencils.

2. The structure set forth in claim 1 wherein the separator sheets are coated with a silicone resin to repel the adhesive of said stencil.

3. The structure set forth in claim 1 wherein the size of the separator sheets is slightly larger than that of the stencil sheets and the size of the container is slightly larger than that of the separator sheets.

References Cited in the file of this patent UNITED STATES PATENTS 1,066,585 Cox July 8, 1913 2,248,317 Van Cleef July 8, 1941 2,323,342 McManus et al July 6, 1943 2,462,242 Webb et a1 Feb. 22, 1949 2,588,812 Dougherty Mar. 11, 1952 2,771,026 Mooney Nov. 20, 1956 2,840,080 Clark June '24, 1958 2,917,167 Gregory et a1 Dec. 15, 1959 

1. A PACKAGE COMPRISING A PLURALITY OF STACKED STENCIL SHEETS OF THE TYPE HAVING A NORMALLY TACKY NON-DRYING ADHESIVE PORTION, A SEPARATOR SHEET HAVING ADHESIVE REPELLENT SURFACES ON BOTH SIDES THEREOF AND INTERPOSED BE- 